How do you sand your CNC carvings?

[Jim Underwood]

How do you sand your CNC carvings?

I'm finding that there are areas that no matter how fine your stepover is, it's still very difficult to get the lines out.

I'm wondering if there's a good way to sand these things other than by hand and a lot of patience.

[Jerome Stanek]

a sanding mop

[Jim Underwood]

Have any recommendations?

[Rich Fennessey]

Here is discussion on the Camheads forum regarding this. One guy suggested using oil on the piece and recut the next morning.
camheads.org/showthread.php?t=2327&highlight=flap+sander

[Gene Crain]

http://solutions.3m.com/wps/portal/3M/en_US/Marine/Home/Products/Catalog/?PC_7_RJH9U5230GE3E02LECIE20S4K7000000_nid=1V4RW4V 6P8beRJ5GMFSMV0gl

[Paul Phillips]

Hi Jim,
Can you post a picture so we can understand better what you are trying to sand? If it's very intricate there's no easy way to do it other than by hand that I know of. I use mostly HDU though so it's generally easier to sand than wood, I typically use a DA sander and hand sand the rest, I prime and paint my pieces though, so that makes it easier to hide tool marks as well. I used to do carve it all by hand also, so I figure I'm way ahead of what it used to take me to do it all by hand. :) Sometimes I still use my hand carving chisels to help smooth things out and finish-up the final piece, that really helps.
Paul

[Jim Underwood]

Paul,

Take a look at the vanity apron I posted. That's typical of something I'd want to sand.

[Gene Crain]

on vectric forum there are some good threads about detail sanding

[Paul Phillips]

Jim, I see what you mean, that's very nice work and some very fine detail involved, wish I could help you more but maybe Gene's ideas are worth a try.
Paul

[Keith Outten]

Take a look at this link and scroll down to the very bottom of the page.

http://www.vectric.com/media/files/cool-stuff/projects/2013/02-feb/Better-Than-Sliced-Bread_BreadBox_Project_Tutorial.pdf

3M Radial Bristle Discs from
(stack 3 discs at a time on your rotary tool mandrel)
80-grit: part # 4494A19
220-grit: part # 4494A18
www.mcmaster.com

[Mike Heidrick]

If you have the time - run the job a second time. You would be surprised at the vcarve results.

[JERRYWAYNE MILLER]

The best thing I found to eliminate the "fuzzies" is sandblasting with a light medium(baking soda,walnut shells,etc.).

[Jim Underwood]

I finally resorted to using some sticky backed sandpaper folded over on itself, cutting it into 3/4" squares, poking a small hole in it for my Dremel tool's mandrel, and sanding the ridges and fuzzies out of the vertical walls with that. It worked fairly well, but I think I'm going to get some of the sanding mops or the 3M radial bristle things, and perhaps a Foredom tool.
,
In addition to the cusp lines from the raster cut, there are the "fuzzies" spoken of above. The worst problems, however, are the ridges left in curved vertical walls because of the stepover. Unless you have a really small bit and really small stepover, I'm not sure how you would eliminate these.

[Mike Heidrick]

Also make sure your machine is trammed and the bed is surfaced.

[Gene Crain]

artcam has a rest machining feature which assigns vectors to the relief and using a profile toolpath offset inwards helps remove some of the cusp lines

[Jim Underwood]

Gene, I'm familiar with the "machine rest" feature. Unfortunately I've not found it to be worthwhile. It causes more problems than it solves. I'd rather just go back with a smaller bit and recut the whole thing on a bias to the first cut.

Mike, this Komo remains pretty true most of the time. I think the last time I trammed it, I was good to a couple thousands in a 24" circle. And the spoilboard gets resurfaced about 2 or three times a month depending on how badly it gets cut up from running thousands of cabinet parts across it.

I think the solution is to stock sanding mops of some kind and get a Foredom tool to run them.

[Mike Heidrick]

Try one time to run it twice and see if I am crazy. :)

[Paul Phillips]

Or, if you decide to run it twice and have the time, try using a smaller ball-nose bit with 85-90% overlap.

[Shari Loveless]

Jim,
I've been sanding our carvings for quite a while now and I've used many different tools and done lots of testing of different methods. I always end up using my own homemade sanding mops that fit in my hand machine (hanging mastercarver with a foot control). The foot control is great for varying the speed of the mop rotations. I cut my strips of fabric backed sandpaper the right length, slit the ends, poke a hole in center, and then layer onto mandrel. Layers will vary from 4 to 12. I make some of them soft and long to reach into skinny areas, some short and thick for sanding around the outside edges of inset, and just average size and thickness for overall general sanding of the whole design. When I make the mops, I make six of each grit and size. This way I have enough to sand a couple of projects without interruption. I use 1/8, 1/16, 1/32 bits when we carve our designs. I don't want to lose any of it during sanding and our homemade mops work great. I tried the 3M bristles and didn't care for them that much...they have their own issues. Making my own mops and adjusting my speed and hand pressure gives me precise control over the process. I'm sure everyone has their own likes and dislikes. You'll just have to do some experimenting of your own to find what works the best for you. Each type of wood and carving will dictate it's own needs as well. Success is finding what does a suitable job and makes the process enjoyable.

[Jim Underwood]

Great info! Perhaps this old widebelt sander paper will serve in a second life. They are a little coarse though.
I do think an investment in a rotary tool is in order.

[Shari Loveless]

Just make sure you get one with a big enough motor to go the distance. I burned up 3 good dremels in short order before I got the mastercarver with the 1/2 hp motor. It's pretty much a large motor with a flex shaft attached but it can definitely handle all I've been putting it through. Those old belts should re-purpose nicely into mops.

[Jim Underwood]

I currently have a Dremel that is very lightly used. I understand they are easily burnt up. So I've not let anyone else use it. I've been looking at Foredom tools for the few carvings we do. I'd rather not burn up my personal tool for my employer.
I wish the boss was convinced we could make money carving. He doesn't want to spend money on tools or training/practice time for it. The sad thing is that every time I get a chance to make carvings they want it done quick. If you want it done quick you have to invest in those things beforehand.
When I made the mantel carving for our showroom it took two days for someone to sand it out. It would have been cheaper and quicker to run the 1/16th bit over the entire thing and buy a rotary tool and sanding mops.

[Viktor Zsigrai]

jim

it is very true... people thinking when theyre see the much machine time that by hand migth faster..
machine always cheaper than human workforce..

the restmachining really dont work, because wood is always in movement.

whne i had bad spots i calculated only around that area toolpath with smaller tool..
and set the smaller tool to the already milled surface.. close to the spot..

from gcode i got the x-y-z cordinata

moved the smaller ballend mill over and set manually the z value.. i dont know how it could work on your komo.. they are real big machines..

for your shop migth would be affordable a simpler cheaper machine only for finish machining.. even a machine runs 8-12 hour a small machine just use little power and one ball endmil.. way cheaper than any human workforce..

while your komo migth using 30 or more kw per hour a small machine migth runs with a few kw..

folks cant imagine a few palmsized carving if detailed, takes day to sand out by hand.. and bristles can sand out fine details..

[Russ D Wood]

I use the sanding mops from StockRoom Supply. They work really well. I use them in a powered hand drill so I can vary the speeds. Russ

http://www.stockroomsupply.ca/shop/sanding-mops.html?SID=97da2c7ea1bb0784b777190b14794593

[bobby milam]

I have tried sanding mops but haven't mastered them yet as I remove more of the carved detail than the problem areas. I really like scrapers and recently bought on of these.

http://www.woodcraft.com/product/2021180/31455/flexcut-woodworkercarver-profile-scraper-set-w-power-handle.aspx

It tells you on the package that they are useable out of the package but need to be sharpened for best results. They work pretty good for me. I am going to sharpen them this weekend and see how much better they get.

[Mark Smith61]

I was just about to ask if anybody had tried sandblasting. I was thinking a real fine grain sand and being very careful with the settings, but I never thought of using banking soda or walnut shells. I'm not that familiar with sandblasting other than some I did years ago to remove some rust on car parts, is the walnut shell something you can buy that is designed for sand blasters?

[Jim Underwood]

Holy Moly! Just got a look at the pricing for the 3M bristle discs... :eek:

They sell 'em by the case for $175:
http://www.shop3m.com/61500151594.html?WT.ac=POW_Marine_GS

Fortunately you can buy them by the each from McMaster Carr:
http://www.mcmaster.com/#abrasive-bristle-discs/=nx1ghr

[Bruce Page]

Also available on Amazon: http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=Scotch-Brite%E2%84%A2%20Radial%20Bristle%20Disc

[bobby milam]

Holy Moly! Just got a look at the pricing for the 3M bristle discs... :eek:

They sell 'em by the case for $175:
http://www.shop3m.com/61500151594.html?WT.ac=POW_Marine_GS

Fortunately you can buy them by the each from McMaster Carr:
http://www.mcmaster.com/#abrasive-bristle-discs/=nx1ghr

Thanks for that link. I definitely need to order some and those prices are just right.

[Bruce Kinney]

Hello Jim, My personal experience with carvings done on my CWs has brought me to three primary aids for the finish sanding.

For step marks I go at the "finished carving" first with 4" diameter stacked sanding mop starting with 180 grit in my hand drill.

Next a set of small diamond coated riffler files about 3/16" wide. A quick internet search should show you several choices. These allow me to concentrate on areas that show heavy fuzzies the mop did not clean up and are more detail orientated than sandpaper alone.

Then back to my mops at 220 and 320m grit in the cordless drill. And finally fine adhesive backed sandpaper on a sanding pad to clean and smooth and large face planes and edges. This has brought my clean up time down to less than 1/2 hour for most plaques even with a high level of detail and routed edges to make them stain and finish ready. My apology in that I'm still rather clumsy learning how to post photos here.

273360 273361 273362

[Bruce Page]

Beautiful work Bruce! Where did you find the dragon model?

[Jim Underwood]

Thanks Bruce!
When are we having a CW getogether at your place? Hands on experience is the best way to learn! ;-)

[Bruce Kinney]

Good morning Folks,

It's nice to be retired and answer questions promptly on a Monday morning rather than have to put this off until the following weekend. Finally after 45 years.

Bruce, thanks for your question. The Dragon with castle (I like to think of him/her as Nessie in Scotland) is from the VectorClip3D patterns subscription service. I use thousands of their designs. Happy to advise more offline.

Jim we'll be getting together soon I hope as the North GA CarveWright User Group. I agree that the best way for all of us to learn is from each other and that is how I got into CNC work in the first place after a lifetime of hand carving, computer graphics and carpentry in general. Still trying to round up all the user names and emails in our area so we don't exclude anyone who might like to participate. More to follow.

One more tool I neglected to mention would be small diamond coated burrs chucked in a Dremmel tool. The burrs from Harbor Freight and other sources come as a set of about 10 with sharp and curved cones, cylinders, ball tips etc at about 1/8" dia to max 1/4" tips. I bought two sets large and small for about $10 each. Used with a light touch they are great for the equivalent of 80 grit sanding at high speed in a very controlled area where needed.

Some fuzz areas I have found are much easier to remove after you have sanded and stained the piece. Let it dry, light sand and then apply first coat of your chosen finish. Then when you sand that coat with a mop the fuzzies are stiffened and will be knocked off where they just bent or layed over before.

Hope that adds something to the ideas bucket for everyone.

Fair winds,

Capt Bruce

[Bruce Page]

Bruce, thanks for the info. I will try to locate the model, my granddaughter will love it!

[Roy Harding]

What I find works well for me on the Shopbot is to do the finishing tool path twice. I use a 1/16" inch tapered ball end, with a 7% step over (for you Carvewright users out there - this is the Carvewright "carving bit" - I still get them from CW Parts (http://www.cw-parts.com/), as I did when I was running a CW). The raster pattern follows the Y axis ("up and down") on the first pass, and the X axis ("side to side") on the second pass. If some quick sanding is still required after that - I use a sanding mop in my drill press.

This DOES take time - but as someone above mentioned, machine time and router bits are cheap compared to MY time spent on sanding. I also use the Vector Art 3D patterns - there are other suppliers out there as well.

Some (mostly of keepsake boxes - I REALLY need to hire a kid to get that site organized with all my photos) of my work can be seen here (http://www.flickr.com/photos/oldebulle/).

[Bruce Kinney]

Beautiful work Roy and I really envy your wide drum/belt sander. Not to go off topic but are your box lids with contrasting wood carvings on top made separately or carved as two glued up layers carved all at once.

[Roy Harding]

Beautiful work Roy and I really envy your wide drum/belt sander. Not to go off topic but are your box lids with contrasting wood carvings on top made separately or carved as two glued up layers carved all at once.

The inlays are cut separately and glued into pockets on the lids (or chest fronts). Using Partsworks (a subset of Aspire which came with the Shopbot) makes it REALLY easy to cut the pockets perfectly.

[Bruce Kinney]

Thanks Roy, It's interesting to see how people approach each project. Same should work on the CW using a pattern outline copied and placed on the back board as a carve area with minimal depth. Time for an experiment with some cedar and elm for contrast.

[Roy Harding]

Thanks Roy, It's interesting to see how people approach each project. Same should work on the CW using a pattern outline copied and placed on the back board as a carve area with minimal depth. Time for an experiment with some cedar and elm for contrast.

Yup - it'll work. I used to do the same thing on my CW.

[Jim Underwood]

I'm not seeing any of Roy's work on this thread... What were you commenting on, Bruce?

[Roy Harding]

I'm not seeing any of Roy's work on this thread... What were you commenting on, Bruce?

He's looking at photos on the link I provided earlier (it's not always easy to see links). The link is here. (http://www.flickr.com/photos/oldebulle/) (Click on the blue text)

[Ralph Y Thorne]

Beautiful work Bruce. Glad to see you sailed up the river to Sawmill Creek.

Ralph

[Bruce Kinney]

Good morning and thank you for the welcome aboard Ralph. Wanted to break out and bit and see what I was missing since so many people speak well of the community here at Sawmill Creek. So the old Riverboat Capt finds himself here up the Creek without the proverbial paddle and causing confusion for Jim. Panic, confusion, disorder . . . my work here is done!

[Michael Kowalczyk]

Hey Jim,
A few thoughts to consider:
1 sharp bits
2-Species
3- direction of grain to toolpath
4-how solid is your material fixtured to your table
5- moisture
6_speed of feed aka G01
7-quality of 3D drawing/model zoom in real close in Artcam to see how smooth the surface is
8- are you doing an X or Y tool-path or a spiral

The above does not imply any of the items are wrong just places to look to see if there is room for improvement.

Sometimes you can run a 2nd finish path with a slightly larger or smaller offset so the tool path will hit different areas and can possibly be run at a MUCH higher speed.

Are you doing one offs or wanting to do production runs?

let me know if anything above helps or works.

thanks and ...

[Jim Underwood]

Good things to consider!

I'd never thought of moisture content since I've always cut kiln dried wood. I know wet wood cuts easier from my woodturning though! Love to make streamers with a gouge!

As for sharp bits, I'm always using that Onsrud three flute 1/8" tapered ballnose that you can only get from Beckwith Décor. I run that in a raster cut with a little less than 10% stepover (.010") with about 200IPM feed and plunge rate. I'm only doing one off stuff most of the time, but I still like to get done as soon as possible, because it's hard for me to justify cost to Joe Homeowner. Of course when you figure in sanding time, you'd be better off running a 1/16" bit after anyway. I think I'll try running a second pass with the 1/16" bit running at .006" stepover and just run the speed way up there.

I also never thought of the part moving on the table while carving. If you don't have rigidity when machining, you don't have nuttin. Of course a 25 HP Kaeser vacuum pump helps relieve any anxiety on that score... ;)